A clock pendulum oscillates at a frequency of 1. At t = 0, it is released from rest starting at an angle of 12 to the vertical.

A clock pendulum oscillates at a frequency of 1.2 Hz. At t = 0, it is released from rest starting at an angle of 12° to the vertical. Ignoring friction, what will be the position (angle) of the pendulum at the following times? (Hint: Do not confuse the angle of swing θ of the pendulum with the angle that appears as the argument of the cosine.)
(a) t = 0.25 s
1°
(b) t = 1.60 s
2°
(c) t = 500 s
3°